function externalLinks() {
	if (!document.getElementsByTagName) return;
	var anchors = document.getElementsByTagName('a');
	for (var i=0; i<anchors.length; i++) {
	var anchor = anchors[i];
	if (anchor.getAttribute('href') &&
		anchor.getAttribute('rel') == 'external')
		anchor.target = '_blank';
	}
}
window.onload = externalLinks;